Telecommunications

There is a way to use dying UHF channels for 'super Wi-Fi' data connections

There is a way to use dying UH...
Rice researchers used WARP, the wireless open-access research platform, to build the system
Rice researchers used WARP, the wireless open-access research platform, to build the system
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Rice University engineers have demonstrated the first system that allows Wi-Fi data transmissions over UHF channels during active TV broadcasts
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Rice University engineers have demonstrated the first system that allows Wi-Fi data transmissions over UHF channels during active TV broadcasts
Rice researchers used WARP, the wireless open-access research platform, to build the system
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Rice researchers used WARP, the wireless open-access research platform, to build the system

To say that pulling data out of the air via a Wi-Fi connection is more popular in the United States than pulling down a video signal from a local UHF television station probably won't come as a surprise to most Americans, but use of the UHF spectrum is still prioritized for TV signals. Now researchers at Houston's Rice University have demonstrated how UHF frequencies can be used for so-called "super Wi-Fi" without significantly interfering with legacy TV broadcasts.

“Due to the popularity of cable, satellite and Internet TV, the UHF spectrum is one of the most underutilized portions of the wireless spectrum in the United States,” said lead researcher Edward Knightly. “That’s a bitter irony because the demand for mobile data services is expected to grow tenfold in the next five years, and the UHF band is perfectly suited for wireless data.”

UHF takes up the space between 400 and 700 megahertz on the wireless spectrum. Its signals can carry for miles and more easily penetrate walls and trees than the higher frequencies used for most wireless routers. Despite this and the growing demand for wireless data, TV broadcasters continue to maintain preferential access to the UHF spectrum, even as the percentage of Americans relying on over-the-air signals for TV programming has begun to dip into the single digits in recent years.

The Federal Communications Commission allows for data to be transmitted over open UHF channels not claimed by a TV broadcaster, but urban areas where the need for more Wi-Fi options is greatest are also the least likely to have unclaimed UHF frequencies.

Knightly and Rice graduate student Xu Zhang designed a new solution to allow for transmitting wireless data over UHF channels during TV broadcasts over those same channels called WATCH (for “Wi-Fi in Active TV Channels”) and were granted permission from the FCC to test it on the Rice campus last year. The basic idea behind the system is to actively monitor nearby TVs that are tuned into a local UHF video signal and to use advanced and efficient signal-canceling technology to send wireless data over the same channel without interference between the data and video transmissions.

Rather than adding new technology to existing UHF TV transmitters, the system relies instead on actual television sets reporting when they are being tuned to a UHF channel via smart TV remotes or possibly through integration in next generation TVs. When a TV tunes itself to a UHF station, the Wi-Fi system then shifts its data transmission to an unused part of the UHF spectrum.

“Our tests showed that WATCH could provide at least six times more wireless data (over existing UHF spectrum),” Knightly said, adding that the system only added a fraction of a second delay to tune a test television equipped with WATCH to a UHF video broadcast, which was practically imperceptible to a person switching channels.

“Allowing the UHF spectrum to be inefficiently used makes little sense today and will make even less sense in the future... There are already more people in the United States who require mobile data services than there are people using broadcast-only TV."

A report on the research was presented at Association of Computing Machinery’s MobiHoc 2015 conference in China.

Source: Rice University

4 comments
Dan Parker
The article says, “UHF frequencies can be used for so-called "super Wi-Fi" without significantly interfering with legacy TV broadcasts.” Define, “significantly”. Right now in our area, the TV broadcast signals are tenuous at best. It doesn’t take much interference to get the black screen with the box that says “weak or lost signal”. It’s irritating and any plans to make TV signals more unstable will be met with resistance. I’ve chosen not to pay for cable or satellite TV, preferring instead to use that money to buy food and other necessities. I refuse to be bent over for content that mostly consists of advertising, reruns of old movies and infomercials, paying an amount equal to monthly rent on a small apartment back in the ‘70s. But, there are many who rely on broadcast television who cannot afford the exorbitant, monthly premiums charged by cable and satellite companies. Those less fortunate, unsurprisingly and as usual, are the ones who will ultimately pay the price for your super Wi-Fi that could have been attained through other means.
JaxCavalera
@ Dan, I agree with your sentiments on the matter regarding having to pay .. for the privileged of being sat in front of programmed tv with advertisements and infomercials. I believe that a much larger spectrum of shows can be obtained for free off the internet and things like Youtube are getting more eyeballs than tv ever did because it can accompany the end user regardless of their mobility and provides 100% freedom of choice. If watching advertisements *and providing content providers on youtube* isn't your thing, a simple addon called AdBlock Plus will do the trick. I think UHF as a medium for transporting television content could be better utilized for other things based on the current statistics etc. In Australia, we got rid of UHF etc for our broadcast infrastructure a few years back so a technology like this over here wouldn't even have a negative impact.
christopher
@Dan - if you booted all those fossils off UHF, you'll actually be doing them a favor. You and they alike are the digital equivalent of a handful of pedestrians walking down a multi-lane freeway, and forcing all the cars to crowd into the dirt tracks on the side because you few are hogging the almost-empty roadway, and blatantly wasting all of its potential in the process.
EH
Television shouldn't be regarded as a positive cultural force, but as pollution of the airwaves with advertising, propaganda, and ever-more degenerate and degrading mental sewage. There are better uses for this bandwidth. There are also better uses for the bandwidth of cable TV; the cable providers have been making obscene profits on their monopolies for far too long. Pull their operating licenses and buy out their plant for what it is worth in the absence of an operating license (scrap.) Use the cable system as a backbone for a national system of free access low-power cellular-internet UHF hotspots and the taxes on the resulting increased economic activity would likely more than pay for operating costs. Internet access should be treated as a public good of the same type as road access.